A variety of tool attachments have been provided for use with powered digging or material-moving apparatus such as excavators, front end loaders, backhoes, bulldozers and the like. Such apparatus typically includes one or more supporting arms at the end of which a tool attachment may be pivotally connected.
One tool attachment frequently used with such apparatus is the so-called "bucket" used in many digging and material-moving applications. A wide variety of sizes and shapes of buckets have been provided for various applications. For example, the so-called "digging" bucket is a relatively heavy duty bucket used for moving material such as blasted rock, heavy gravel, or compacted earth. "Digging" buckets may be supplied in varying widths. The so-called "clean-up" bucket typically comprises a relatively wide bucket used primarily for carrying material from one location to another as, for example, loading earth onto a truck. Another attachment is the so-called "V" bucket (also known as a "ditching" bucket) used in forming a V-shaped ditch. Other common tool attachments include "rakes" (used for clearing brush and the like), "clamshells" (also known as "grab-buckets", essentially comprising two buckets hinged together to form an inverted scoop which may be lowered in the open position onto a pile of material and then closed over the material to entrap some material for movement to another location) and the so-called "ripper" (usually comprising a tooth-shaped member and used to break up hard material which may then be moved with one of the bucket-type attachments).
During operation of such apparatus, the operator may find it desirable to interchange tool attachments to perform different tasks. For example, an operator moving loose material with a bucket-type attachment may encounter hard material which requires breaking up into relatively small pieces before it may be moved with the bucket. In such a case, the operator may wish to replace the bucket with a "ripper", use the "ripper" to break up the hard material, then replace the "ripper" with the bucket and continue moving the broken material.
The mechanism typically provided for use with such apparatus to secure a tool attachment to the end of an arm often includes one or more pins which are inserted in apertures located near the end of the arm and in co-operating apertures in a hook-up mechanism fastened to each tool attachment desired to be used with the apparatus. Fastening members are also usually provided to prevent the pins from working free after they have been inserted. To remove a tool attachment which has been affixed to the end of an arm, the operator must dismount the vehicle, manually remove the pin fastening members and drive the pins out of the arm apertures and co-operating apertures of the hook-up mechanism. To secure a different tool attachment to the arm, the operator must then remount the vehicle and position the arm to align the apertures in the arm with the co-operating apertures of the hook-up mechanism of the tool attachment which is to replace the removed attachment. The operator must then dismount the vehicle again, manually insert the pins in the aligned apertures and replace the pin fastening members before he can recommence operations.
Obviously, it is relatively time consuming for the operator to interchange tool attachments as described above. Powered digging and material-moving apparatus is typically very expensive to operate, and it is therefore desirable to maximize the time during which the apparatus is performing its intended function and to minimize the time taken for such non-productive tasks as interchanging tool attachments. A coupler would clearly be useful to assist the operator in interchanging tool attachments. With the typical mechanism described above, the operator must dismount the vehicle at least twice to manually remove and then replace the pins and fastening members. Of course, the operator would not have to dismount if a second man is available to assist him. However, a second man is not always available and, if one is, then his presence would probably necessitate further expense and time would still be required for him to manually remove or replace the pins and fastening members.
One improved coupling mechanism which has been provided comprises a link mechanism pivotally mounted at the end of the arm and a cooperating hook-up mechanism, rigidly affixed to each tool attachment of interest. To couple an attachment to the arm, the operator must position the arm and its attached link mechanism to engage the hook-up mechanism of a selected tool attachment. The operator must then dismount the vehicle to manually fasten the link mechanism and hoop-up mechanism together by inserting a wedge-type device into co-operating apertures in the link mechanism and hook-up mechanism, and then secure the wedge in place with one or more bolts to complete the coupling of the tool attachment to the arm. To remove the attachment, the operator must again dismount the vehicle and manually remove the bolts and the wedge before the arm may be manoeuvred free of the attachment for securing to a different attachment. Although this coupling mechanism provides some improvement in reducing the number of manual operations required to interchange attachments, it still requires a considerable amount of time and requires the vehicle operator to dismount the vehicle at least twice during the interchanging operation, unless a second man is available to assist him.
Use of such prior coupling mechanisms may prove frustrating to the operator, who may feel that it would take an unreasonable amount of time for him to dismount and remount the vehicle twice to perform the cumbersome task of manually unfastening and re-fastening such prior coupling mechanisms. This may encourage the operator to use a tool attachment to perform a function for which it was not primarily intended, which may damage the attachment, or result in decreased productivity during use of an attachment to perform a task for which it was not primarily intended. Furthermore, use of a tool attachment unsuited to the task at hand may prove dangerous.
Accordingly, it is an object of the present invention to provide a coupler which substantially reduces the number of manual operations required to interchange tool attachments on a supporting arm. A related object is to provide a coupler which permits rapid interchanging of tool attachments.
A further object is to provide a coupler which is simple in construction, uncomplicated in its operation and easy to use.